1. Field of the Invention
This specification relates to a noise decreasing type electromagnetic switch capable of noise generated between a stationary core and a movable core.
2. Background of the Invention
In general, an electromagnetic switch is located between a battery and a direct current (DC) power converter of an electric vehicle, such as a hybrid car, a fuel cell car, an electric golf cart, an electric folklift truck and the like, and serves to supply power of the battery to the power converter, and supply power generated from a power generator to the battery.
The electromagnetic switch includes a coil which is excited (magnetized) or demagnetized according to whether or not a control current flows, a yoke installed around the coil to define (form) a magnetic path in the vicinity of the coil, a metal plate installed to face the yoke and defining the magnetic path around the coil together with the yoke, a stationary core fixed to the metal plate, a movable core installed to face the stationary core, and movably installed to contact the stationary core when the coil is excited and to be separated from the stationary core when the coil is demagnetized, a shaft having one end portion coupled to the movable core and movable together with the movable core, and a return spring located between the stationary core and the movable core and having a larger elastic force than contact pressure of a contact spring such that the movable core is separated from the stationary core.
In the structure of the related art electromagnetic switch, when a magnetic field is formed in response to power being applied to the coil, the movable core is attracted toward the stationary core, and an upper conductive portion is run by the shaft connected to the movable core. However, impact noise may be generated while the shaft movable in cooperation with the movable core contacts the stationary core, thereby causing degradation of a perceived quality of a product.